1. Field of Invention
The present invention relates to a method of improving fuel economy through electric vehicle (EV) control of a hybrid vehicle having various modes, and more particularly, to a method of improving fuel economy through EV control of a hybrid vehicle having various modes in which fuel economy may be improved by strategically turning on or off the hybrid vehicle in an input split and a compound split.
2. Description of Related Art
Generally, a hybrid vehicle uses not only an engine but also a motor as a power source so that emission of exhaust gas may be reduced and fuel economy may be increased.
The hybrid vehicle may be driven in an electric vehicle (EV) mode that is a purely electric vehicle mode in which only power of a driving motor is used. In the EV mode, power may be generated by the driving motor based the electric power and SOC of a battery. The hybrid vehicle may also be driven in a hybrid electric vehicle (HEV) mode in which power of an engine that generates power by fuel and power of the driving motor are both used as power source. Further, the hybrid vehicle may be driven in a regenerative braking (RB) mode in which braking and inertial energy of the hybrid vehicle is recovered by the driving motor, which generates electricity to be charged in a battery, when the hybrid vehicle is driven by the braking or inertial energy.
The hybrid vehicle has fuel economy including momentary fuel economy that is an amount of fuel consumed when generating power by the power of the engine, the momentary fuel economy being shown as a gauge through a cluster, and accumulative fuel economy that is accumulative fuel amount. When the hybrid vehicle is driven in the EV mode, maximum fuel economy of the battery the hybrid vehicle can output through battery power is displayed through the cluster.
Namely, as shown in FIG. 1, the HEV system described above includes multiple clutches and a brake and can implement various EV types. When the engine is started in a mode corresponding to the input split, the engine is started while only a second brake BK2 is fixed.
The driving mode may be implemented in five driving modes including an input split, a compound split, a fixed gear level one, a fixed gear level two, and a fixed gear level three.
However, in the five driving modes mentioned above, there is a problem in that the EV is available only in the input split mode, and in order to enter the EV in the other modes, the input split mode must be first selected to enter the EV.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.